Dreaming of 8 degrees BTDC

[keithTVR350i]

Is my car unique in not being able to run more the 3 degrees BTDC before it pinks like hell ?
Co is 3%, cool plugs, new wires, 80 degrees running temp and running super unleaded.
Is there access to the distributor weights ?
Losing 5 degrees probably equal to a few BHP.
Any suggestions ?
Cheers Keith

[keithTVR350i]

Hi Mark, I have a feeling it could be clogged injectors or the ECU, I have an FSE regulator and it runs 2.7 bar. Is it worth running with injector cleaner ? If it is a ECU fault is it easy to remedy ?
Thanks
Keith